Before attempting to use gels it is advantageous to have an understanding of lighting control, colour temperature (White Balance) and colour theory. Often when dealing with multiple light sources and using more than one colour gel to add or create effect then understanding and using complimentary colours can offer dramatic impact and effective impact. Before considering attempting to use Gels, it is important to have a good knowledge and understanding of Colour management and colour theory. There are many good quality online resources for in depth information. A good start is to visit either Lee Filters or Rosco Filters web site
Red Cyan Green Magenta Blue Yellow
It's also important in photography to understand Colour Temperature. Different light sources have different colour temperature (measured using units of Kelvin). The Kelvin value/temperature of light will change throughout the day and this colour shift will need to be compensated for. Camera White Balance can be changed within the cameras settings
using Presets, Kelvin or by setting a custom white balance to match the colour temperature of the scene we are recording. When using flash or continuous studio lighting, the use of Technical Gels is preferable as they will affect the colour temperature the light emits. This method offers more precise control. Once a reason for use has been established then the process of selecting which gels to use will then be based on choice. There are three categories I use to establish my choices:
Control
Creative Control,
Creative
Each have their own individual uses yet they are flexible enough to all work with more or less rigid criteria. These three categories can be used when wanting to manipulate, control, enhance or reduce the effect each light source individually or collectively.
Control
Often used on stage sets where the same scenery is used several times. Control may be used o simulate different times of day or environment. The scenario. On set a couple are sat at the table. By using both Technical / colour Correction Gels and Diffusion Gels we can mimic how this set would look at different time of day or night
Creative control
This image shows how the application of Technica / Colour Correction Gels allows creative control. When shooting this image I selected a Tungsten White balance in camera and used Colour Temperature Orange (C.T.O.) Technical Gels to correct those areas I did not want to look blue.
Technical / Colour Correction gels are available as:
Full CTO "204": 1 stop
1/2 CTO "205": 2/3 stop
1/4 CTO "206": 1/3 stop
1/8 CTO "223": 1/3 stop
Note the assigned value and Stop value are different. A 1/4 CTO loses 1/3 stop of the light transmitted through it. Many gel sheets have info printed along the edge at intervals. They are numbered for easy recognition allowing greater control when stacking more than one gel. Understanding how much compensation is required to compensate for light loss through the gel allows more accurate results.
Creative
This last image shows how we can apply the use of Colour Effect Gels with a single reason. To add colour.
This image was shot for a magazine feature where the brief was to use reflected coloured light. The lights used for this image were set, gelled and metered. The different coloured gels used were chosen solely for their artistic or creative effect.
The studio set and dress for this image were both created using highly reflective Silver Mylar sheeting which was deliberately creased to effect how the different coloured lights would be reflected. Four studio flash lights were used with three of these flash heads having different Colour effect Gels attached. The fourth flash had no gel attached and was used to add a neutral light the models face.
For most creative work it is possible to achieve dramatic images using a few gels and speed lights.
It’s well Gel
Manipulate to correct, or manipulate for effect.
Why use Gels? Gels are often used to add Creative colour effects or allow Creative Control or simply Control lighting. Gels can be categorised into three types: Colour Effect Gels are often used for artistic purpose to add or manipulate colour to an image. Colour Correction Gels /Technical Gels offer the ability of technical correction for colour temperature .This type of gel allows the ability to control erroneous light colour. Diffusion Gels allow the control of shadows
A word on Safety… Do not use cheap coloured plastic as with some lights these can quickly overheat and catch fire. I use high quality Gels from Lee Filters.
